Has anyone taken this onboard a United airlines flight? I’ll be flying with them in August and would like to know if it would fit in the overhead bin.

Yes. My sister-in-law just took this stroller on a very full United flight last week. They did not have any trouble putting it in the overhead bin. The gate agent did ask if they needed a gate check tag for it when we were preparing to board. Her husband replied no, it folds down to a size that fits in the overhead. Agent said ok and didn’t give them any hassle.

Is it compatible with maxi cosi coral xp car seat?

The Metro+ Car Seat Adapter is not compatible with the Maxi Cosi Coral XP.

Is there anyway to avoid the " clicking" sound when lowering the canopy? It is so loud and would easily wake the baby?

Unfortunately, the clicking noise is the sound of the sunshade opening and closing.

Is the handle height ergonomic for a 6ft tall dad? I see it’s adjustable, but is it tall enough to prevent me from hunching or kicking the rear axle?

My husband is 6’4” and he has no problems with kicking the wheels/ basket. We got this specifically due too our 1ft height difference. Only travel stroller we can find that has teloscopic handle